fix: Graceful shutdown for all UDFs

[BulkBeing]

Kindly explain what this PR does.

[codecov]

Codecov Report

❌ Patch coverage is 65.55184% with 103 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.98%. Comparing base (bcdc4c3) to head (6c37cb5).

Files with missing lines	Patch %	Lines
.../pynumaflow/accumulator/servicer/async_servicer.py	37.50%	14 Missing and 1 partial ⚠️
...flow/pynumaflow/sourcer/servicer/async_servicer.py	68.29%	7 Missing and 6 partials ⚠️
...pynumaflow/sourcetransformer/servicer/_servicer.py	55.55%	10 Missing and 2 partials ⚠️
...low/pynumaflow/mapper/_servicer/_async_servicer.py	70.58%	3 Missing and 2 partials ⚠️
.../pynumaflow/mapstreamer/servicer/async_servicer.py	70.58%	3 Missing and 2 partials ⚠️
...flow/pynumaflow/reducer/servicer/async_servicer.py	75.00%	3 Missing and 2 partials ⚠️
...flow/sourcetransformer/servicer/_async_servicer.py	70.58%	3 Missing and 2 partials ⚠️
...flow/pynumaflow/mapper/_servicer/_sync_servicer.py	85.18%	2 Missing and 2 partials ⚠️
.../pynumaflow/pynumaflow/accumulator/async_server.py	66.66%	2 Missing and 1 partial ⚠️
.../pynumaflow/pynumaflow/batchmapper/async_server.py	66.66%	3 Missing ⚠️
... and 11 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #337      +/-   ##
==========================================
- Coverage   94.34%   91.98%   -2.37%     
==========================================
  Files          67       67              
  Lines        3182     3429     +247     
  Branches      179      215      +36     
==========================================
+ Hits         3002     3154     +152     
- Misses        145      218      +73     
- Partials       35       57      +22     

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